ZyWALL User's Guide

Chapter 28 Anti-Virus
ZyWALL USG 100/200 Series User’s Guide
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• HAV scanners are slow in stopping virus threats through real-time traffic (such as from
the Internet).
• HAV scanners may reduce computing performance as they also share the resources (such
as CPU time) on the computer for file inspection.
• You have to update the virus signatures and/or perform virus scans on all computers in the
network regularly.
A network-based anti-virus (NAV) scanner is often deployed as a dedicated security device
(such as your ZyWALL) on the network edge. NAV scanners inspect real-time data traffic
(such as E-mail messages or web) that tends to bypass HAV scanners. The following lists
some of the benefits of NAV scanners.
• NAV scanners stops virus threats at the network edge before they enter or exit a network.
• NAV scanners reduce computing loading on computers as the read-time data traffic
inspection is done on a dedicated security device.